U.S. patent number 9,004,468 [Application Number 13/985,785] was granted by the patent office on 2015-04-14 for torque rod.
This patent grant is currently assigned to Bridgestone Corporation, Honda Motor Co., Ltd.. The grantee listed for this patent is Naoyuki Kamei, Mutsuo Tezuka. Invention is credited to Naoyuki Kamei, Mutsuo Tezuka.
United States Patent |
9,004,468 |
Kamei , et al. |
April 14, 2015 |
Torque rod
Abstract
It is an object of the present invention to ensure that a torque
rod breaks downward when a predetermined load or greater is input
thereto. A torque rod has a first annular portion (21), a second
annular portion (22), a connecting stay portion (24) that
interconnects the first annular portion (21) and the second annular
portion (22), a first attachment member (31) that is connected via
a first rubber elastic body (41) inside the first annular portion
(21), and a second attachment member (32) that is connected via a
second rubber elastic body (42) inside the second annular portion
(22). The connecting stay portion (24) has an upper fork portion
(24U) and a lower fork portion (24L), and the bending strength of
the lower fork portion (24L) is less than that of the upper fork
portion (24U). A cavity portion (30) to which part of the first
annular portion (21) is exposed is formed between the upper fork
portion (24U) and the lower fork portion (24L). A thin-walled
portion (21A) having a projecting portion (21B) is disposed in a
region of the first annular portion (21) exposed to the cavity
portion (30). A sloping surface (24A) whose lower side slopes
toward the second annular portion (22) is formed in a region of the
cavity portion (30) opposing the first annular portion (21).
Inventors: |
Kamei; Naoyuki (Yokohama,
JP), Tezuka; Mutsuo (Haga-gun, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kamei; Naoyuki
Tezuka; Mutsuo |
Yokohama
Haga-gun |
N/A
N/A |
JP
JP |
|
|
Assignee: |
Bridgestone Corporation (Tokyo,
JP)
Honda Motor Co., Ltd. (Tokyo, JP)
|
Family
ID: |
46879469 |
Appl.
No.: |
13/985,785 |
Filed: |
March 22, 2012 |
PCT
Filed: |
March 22, 2012 |
PCT No.: |
PCT/JP2012/057382 |
371(c)(1),(2),(4) Date: |
August 15, 2013 |
PCT
Pub. No.: |
WO2012/128328 |
PCT
Pub. Date: |
September 27, 2012 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
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US 20130320181 A1 |
Dec 5, 2013 |
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Foreign Application Priority Data
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|
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Mar 22, 2011 [JP] |
|
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2011-062663 |
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Current U.S.
Class: |
267/141.1;
267/276 |
Current CPC
Class: |
F16F
1/3849 (20130101); B60K 5/1241 (20130101); B60K
5/1275 (20130101) |
Current International
Class: |
F16F
9/00 (20060101) |
Field of
Search: |
;188/140.11-141.7,276
;248/548 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
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1810534 |
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Aug 2006 |
|
CN |
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1845833 |
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Oct 2006 |
|
CN |
|
1 666 296 |
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Jun 2006 |
|
EP |
|
2005-083412 |
|
Mar 2005 |
|
JP |
|
2006-112537 |
|
Apr 2006 |
|
JP |
|
2006-205905 |
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Aug 2006 |
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JP |
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2007-069742 |
|
Mar 2007 |
|
JP |
|
Other References
Chinese Office Action, dated Jul. 31, 2014, issued in corresponding
Chinese Patent Application No. 201280007032.3. cited by applicant
.
Extended European Search Report, dated Aug. 18, 2014, issued in
corresponding European Patent Application No. 12761261.2. cited by
applicant .
International Search Report for PCT/JP2012/057382 dated Jun. 19,
2012. cited by applicant.
|
Primary Examiner: Schwartz; Christopher
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
The invention claimed is:
1. A torque rod comprising: a first annular portion; a second
annular portion; a connecting stay portion that extends outward in
a radial direction from an outer peripheral section of the second
annular portion and is continuous with an outer peripheral section
of the first annular portion, the connecting stay portion having an
upper fork portion that is connected to an upper side of the first
annular portion and a lower fork portion that is connected to a
lower side of the first annular portion and whose bending strength
is less than that of the upper fork portion, with a cavity portion
to which part of the first annular portion is exposed being formed
between the upper fork portion and the lower fork portion; a first
attachment member that is placed on an inner peripheral side of the
first annular portion and is connected to a power unit; a second
attachment member that is placed on an inner peripheral side of the
second annular portion and is connected to a vehicle body; a first
rubber elastic body that is disposed between the first annular
portion and the first attachment member and elastically
interconnects the first annular portion and the first attachment
member; a second rubber elastic body that is disposed between the
second annular portion and the second attachment member and
elastically interconnects the second annular portion and the second
attachment member; a thin-walled portion that is disposed in a
region of the first annular portion exposed to the cavity portion;
a projecting portion that is disposed on the thin-walled portion
and is formed convexly in an axial direction of the first annular
portion; and a sloping surface that is formed in a region of the
cavity portion opposing the first annular portion and whose lower
side slopes toward the second annular portion.
2. The torque rod according to claim 1, wherein the upper fork
portion is reinforced by ribs.
3. The torque rod according to claim 2, wherein the projecting
portion is disposed in a position intersecting a direction in which
a load is input to the first attachment member.
4. The torque rod according to claim 3, wherein a protruding
portion that protrudes in such a way as to approach the projecting
portion is disposed in a position on the first attachment member
opposing the projecting portion.
5. The torque rod according to claim 1, wherein the projecting
portion is disposed in a position intersecting a direction in which
a load is input to the first attachment member.
6. The torque rod according to claim 5, wherein a protruding
portion that protrudes in such a way as to approach the projecting
portion is disposed in a position on the first attachment member
opposing the projecting portion.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a National Stage of International Application
No. PCT/JP2012/057382 filed Mar. 22, 2012, claiming priority based
on Japanese Patent Application No. 2011-062663, filed Mar. 22,
2011, the contents of all of which are incorporated herein by
reference in their entirety.
TECHNICAL FIELD
The present invention pertains to a torque rod, and particularly
relates to a torque rod that is a type of mount configuring an
anti-vibration support mechanism for a power unit with respect to a
vehicle body and to which mainly torque reaction force and so forth
spreading from the power unit to the vehicle body is input as an
applied load.
BACKGROUND ART
There has been disclosed a torque rod where a projecting portion
configured to be convex toward an outer peripheral side is formed
on an outer peripheral surface of a rubber elastic body and where a
concave notch portion into which the projecting portion is inserted
is formed in the vicinity of a joint portion where an inner
peripheral surface of a second annular portion joins to a
connecting stay portion (see patent document 1).
Patent Document 1: JP-A No. 2006-112537
SUMMARY OF INVENTION
Technical Problem
Extremely high safety is demanded of vehicles at the time of a
frontal collision or an offset collision, and as a structure that
enhances such safety at the time of a collision on the vehicle
front side, for example, a structure has been developed which
allows the power unit to fall out downward (toward the road
surface) from inside the engine compartment because of a large
impactive load when the vehicle experiences a collision. Because of
this, the power unit and structures around the power unit can be
effectively prevented from moving inward of the vehicle at the time
of a vehicle collision.
In order to realize this power unit fall-out structure, it is
conceivable, for example, to intentionally form a stress
concentration portion in the section of the torque rod that
connects the power unit to the vehicle body, so that, because of a
large impactive load at the time of a vehicle collision,
deformation or destruction starting at the stress concentration
portion arises in a predetermined direction in which the power unit
is to be allowed to fall out.
However, in the conventional example described above, there is the
potential for such a configuration to also end up affecting
strength with respect to twisting force and up-and-down vibration
at the time of vehicle travel for which high strength is demanded,
and there is needed a technology that will allow the power unit to
reliably fall out downward only with respect to an impactive input
in the front-and-rear direction caused by a vehicle collision.
In consideration of the above circumstances, it is an object of the
present invention to ensure that a torque rod can be more reliably
broken downward when a predetermined load or greater is input
thereto, and that a power unit can be allowed to fall out
downward.
Solution to Problem
A first aspect of the present invention is a torque rod comprising:
a first annular portion; a second annular portion; a connecting
stay portion that extends outward in a radial direction from an
outer peripheral section of the second annular portion and is
continuous with an outer peripheral section of the first annular
portion, the connecting stay portion having an upper fork portion
that is connected to an upper side of the first annular portion and
a lower fork portion that is connected to a lower side of the first
annular portion and whose bending strength is less than that of the
upper fork portion, with a cavity portion to which part of the
first annular portion is exposed being formed between the upper
fork portion and the lower fork portion; a first attachment member
that is placed on an inner peripheral side of the first annular
portion and is connected to a power unit; a second attachment
member that is placed on an inner peripheral side of the second
annular portion and is connected to a vehicle body; a first rubber
elastic body that is disposed between the first annular portion and
the first attachment member and elastically interconnects the first
annular portion and the first attachment member; a second rubber
elastic body that is disposed between the second annular portion
and the second attachment member and elastically interconnects the
second annular portion and the second attachment member; a
thin-walled portion that is disposed in a region of the first
annular portion exposed to the cavity portion; a projecting portion
that is disposed on the thin-walled portion and is formed convexly
in an axial direction of the first annular portion; and a sloping
surface that is formed in a region of the cavity portion opposing
the first annular portion and whose lower side slopes toward the
second annular portion.
In the torque rod pertaining to the first aspect, the thin-walled
portion is disposed in the region of the first annular portion
exposed to the cavity portion between the upper fork portion and
the lower fork portion of the connecting stay portion, and the
projecting portion formed convexly in the axial direction of the
first annular portion is disposed on the thin-walled portion, so
when, at the time of a vehicle collision, a predetermined load or
greater has been input from the power unit to the first attachment
member and has been further transmitted from the first attachment
member to the first annular portion, it becomes easier for stress
concentration to arise in the thin-walled portion of the first
annular portion having the projecting portion. Because of this, the
first annular portion breaks starting at the thin-walled portion,
whereby the first attachment member becomes movable backward into
the cavity portion.
In addition to this, the connecting stay portion has the upper fork
portion that is connected to the upper side of the first annular
portion and the lower fork portion that is connected to the lower
side of the first annular portion, and the bending strength of the
lower fork portion is less than that of the upper fork portion, so
the lower fork portion breaks when the predetermined load or
greater is input to the first attachment member.
Moreover, the sloping surface whose lower side slopes toward the
second annular portion is formed in the region of the cavity
portion opposing the first annular portion, so the first attachment
member that has moved backward into the cavity portion and has come
into contact with the sloping surface is guided on the sloping
surface and moves downward. The power unit is connected to the
first attachment member, and the power unit can be allowed to fall
out downward more reliably as a result of the first attachment
member moving downward.
A second aspect of the present invention is the torque rod
pertaining to the first aspect, wherein the upper fork portion is
reinforced by ribs.
In the torque rod pertaining to the second aspect, the upper fork
portion is reinforced by the ribs, and the bending strength of the
lower fork portion is configured to be relatively even lower, so
the lower fork portion can be allowed to break more reliably when
the predetermined load or greater is input to the first attachment
member.
A third aspect of the present invention is the torque rod according
to the first aspect or the second aspect, wherein the projecting
portion is disposed in a position intersecting a direction in which
a load is input to the first attachment member.
In the torque rod pertaining to the third aspect, when the
predetermined load or greater is input to the first attachment
member, the load is concentratedly input to the projecting portion
of the thin-walled portion of the first annular portion. Because of
this, a larger stress concentration arises in the thin-walled
portion of the first annular portion. For this reason, the
thin-walled portion can be allowed to break more reliably.
A fourth aspect of the present invention is the torque rod
pertaining to the third aspect, wherein a protruding portion that
protrudes in such a way as to approach the projecting portion is
disposed in a position on the first attachment member opposing the
projecting portion.
In the torque rod pertaining to the fourth aspect, when the
predetermined load or greater is input to the first attachment
member, the protruding portion of the first attachment member
quickly contacts the projecting portion of the first annular
portion, and the load is transmitted. For this reason, the
thin-walled portion can be allowed to break more reliably.
Advantageous Effects of Invention
As described above, according to the torque rod pertaining to the
first aspect, there is obtained the superior effect that it can be
ensured that the torque rod breaks downward more reliably when the
predetermined load or greater is input thereto, and that a power
unit falls out downward.
According to the torque rod pertaining to the second aspect, there
is obtained the superior effect that the lower fork portion can be
allowed to break more reliably.
According to the torque rod pertaining to the third aspect, there
is obtained the superior effect that the thin-walled portion can be
allowed to break more reliably.
According to the torque rod pertaining to the fourth aspect, there
is obtained the superior effect that the thin-walled portion can be
allowed to break more reliably.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view showing a torque rod that is attached
between a vehicle body and a power unit;
FIG. 2 is a perspective view showing the torque rod;
FIG. 3 is a plan view showing the torque rod as seen from an axial
direction of a second annular portion;
FIG. 4 is an enlarged perspective view showing a structure in the
vicinity of a first annular portion in the torque rod;
FIG. 5A is a main-portion side view showing a state in which the
first annular portion has broken starting at a thin-walled portion
when a predetermined load or greater has been input to a first
attachment member; and
FIG. 5B is a main-portion side view showing a state in which a
lower fork portion of a connecting stay portion has broken and the
first attachment member has moved backward into a cavity portion,
is guided on a sloping surface of the cavity portion, and is moving
downward.
DESCRIPTION OF EMBODIMENT
An embodiment of the present invention will be described below on
the basis of the drawings. In FIG. 1 and FIG. 2, a torque rod 10
pertaining to the present embodiment is a type of mount that is
used in a vehicle and configures an anti-vibration support
mechanism of a power unit 12 with respect to a vehicle body 14, and
the torque rod 10 is disposed between an end portion 12A of the
power unit 12 and the vehicle body 14, for example. The torque rod
10 has a first annular portion 21, a second annular portion 22, a
connecting stay portion 24, a first attachment member 31, a second
attachment member 32, a first rubber elastic body 41, a second
rubber elastic body 42, a thin-walled portion 21A, a projecting
portion 21B, and a sloping surface 24A, and the torque rod 10 is
configured to limit the power unit 12 from being displaced in a
rolling direction and a vehicle body front-and-rear direction, for
example, due to the torque reaction force and inertial force of the
power unit 12.
The first annular portion 21 and the second annular portion 22 are
both configured in substantially annular shapes, and the second
annular portion 22, for example, is formed in a larger diameter
than the first annular portion 21. Further, the first annular
portion 21, the second annular portion 22, and the connecting stay
portion 24 are integrally molded using synthetic resin, for
example, and configure a rod body portion 26. In a state in which
the torque rod 10 is attached to a vehicle, the axial direction of
the second annular portion 22 coincides with the vehicle
up-and-down direction, for example, and the axial direction of the
first annular portion 21 coincides with the vehicle width
direction, for example. For this reason, the axial direction of the
first annular portion 21 and the axial direction of the second
annular portion 22 are orthogonal to one another. The way in which
the torque rod 10 is attached to the vehicle is not limited to
this; for example, the torque rod 10 may also be attached in such a
way that the axial direction of the second annular portion 22
coincides with the vehicle width direction and the axial direction
of the first annular portion 21 coincides with the vehicle
up-and-down direction.
As shown in FIG. 2, the connecting stay portion 24 extends outward
in a radial direction from an outer peripheral section of the
second annular portion 22 and is continuous with an outer
peripheral section of the first annular portion 21. The connecting
stay portion 24 has an upper fork portion 24U that is connected to
an upper side of the first annular portion 21 and a lower fork
portion 24L that is connected to a lower side of the first annular
portion 21. The bending strength of the lower fork portion 24L is
less than that of the upper fork portion 24U, and the lower fork
portion 24L is thinner-walled than the upper fork portion 24U. In
other words, the bending strength of the upper fork portion 24U is
higher than that of the lower fork portion 24L, and the upper fork
portion 24U is thicker-walled than the lower fork portion 24L.
Specifically, the thickness of the upper fork portion 24U is set
considerably higher than the outer diameter of the first annular
portion 21 particularly in the region where the upper fork portion
24U is continuous with the first annular portion 21. In addition to
this, the upper fork portion 24U is reinforced by ribs 28. Not only
is the bending strength of the upper fork portion 24U configured to
be higher than that of the lower fork portion 24L, but also the
compressive strength of the upper fork portion 24U when a load is
input to the first attachment member 31 is configured to be higher
than that of the lower fork portion 24L. In this way, a large
difference in bending strength is disposed between the upper fork
portion 24U and the lower fork portion 24L. Because the upper fork
portion 24U is thick-walled, hollowed-out portions 24B may also be
appropriately disposed in the side portions of the upper fork
portion 24U in consideration of moldability and so forth.
In the connecting stay portion 24, a cavity portion 30 to which
part of the first annular portion 21 is exposed is formed between
the upper fork portion 24U and the lower fork portion 24L. The
sloping surface 24A, whose lower side slopes toward the second
annular portion 22, is formed in a region of the cavity portion 30
opposing the first annular portion 21. The up-and-down dimension of
the cavity portion 30 is set to be the same as or greater than the
inner diameter of the first annular portion 21, for example. This
is to make it easier for the first attachment member 31 to move
backward into the cavity portion 30 when the first annular portion
21 has broken starting at the thin-walled portion 21A at the time
of a vehicle collision.
The thin-walled portion 21A is disposed in a region of the first
annular portion 21 exposed to the cavity portion 30. The
thin-walled portion 21A is a region whose thickness is set smaller
than that of an ordinary portion 21C not exposed to the cavity
portion 30; for example, the thin-walled portion 21A is configured
in such a way that its thickness gradually becomes smaller heading
toward the upper side of the cavity portion 30.
Further, the projecting portion 21B, which is formed convexly in
the axial direction of the first annular portion 21, is disposed on
the thin-walled portion 21A. The projecting portion 21B is disposed
in a position in the thin-walled portion 21A intersecting a
direction in which a load is input to the first attachment member
31. In the present embodiment, the direction in which a load is
input to the first attachment member 31 is a planar direction of
tabular portions 31A of the first attachment member 31. This is
because, as shown in FIG. 1, the tabular portions 31A of the first
attachment member 31 are fixed to the end portion 12A of the power
unit 12 in a state in which the tabular portions 31A are along the
vehicle front-and-rear direction, which is the direction in which a
load from the power unit 12 is input.
In a case where the state of attachment of the tabular portions 31A
with respect to the end portion 12A of the power unit 12 differs
from the above configuration and the direction in which a load is
input to the first attachment member 31 differs from the planar
direction of the tabular portions 31A, the position of the
projecting portion 21B is set using as a reference the direction in
which a load is input to the first attachment member 31.
The range of the projecting portion 21B in the circumferential
direction of the first annular portion 21 is the same as the
thickness of the tabular portions 31A of the first attachment
member 31. How much the projecting portion 21B projects in the
axial direction of the first annular portion 21 is arbitrary. As
shown in FIG. 3, the projecting portion 21B is disposed only on one
axial direction side of the first annular portion 21, for example,
but it is not limited to this and may also be disposed on both
axial direction sides.
In FIG. 1 to FIG. 4, the first attachment member 31 is a rod-like
member that is made of metal, for example, is placed on an inner
peripheral side of the first annular portion 21, and is connected
to the power unit 12. Specifically, the first attachment member 31
is inserted through the first annular portion 21, for example, and
the tabular portions 31A are disposed on both ends of the first
attachment member 31 projecting on both axial direction sides of
the first annular portion 21. Through holes 31B for passing bolts
34, for example, are formed in the tabular portions 31A. As shown
in FIG. 1, the first attachment member 31 is fixed to the power
unit 12 by passing the bolts 34 through the through holes 31B and
fastening the bolts 34 to the end portion 12A of the power unit
12.
A protruding portion 31C that protrudes in such a way as to
approach the projecting portion 21B is disposed in a position on
the first attachment member 31 opposing the projecting portion 21B
of the first annular portion 21--such as, for example, on a base
portion of an end surface 31E of a tabular portion 31A. A center
portion 31D of the first attachment member 31 inserted through the
first annular portion 21 is configured in a cylindrical shape, for
example, and the protruding portion 31C is configured to protrude
further outward in the radial direction than the outer diameter of
the center portion 31D.
Further, as shown in FIG. 4, the protruding portion 31C can be
disposed not just in the position opposing the projecting portion
21B of the first annular portion 21 but also on the opposite side
thereof in the radial direction of the first attachment member 31.
In other words, the projecting portion 31C may be disposed on base
portions of end surfaces 31E on both sides of the tabular portions
31A. This is because, by configuring the first attachment member 31
in this way, the protruding portion 31C can be made to oppose the
projecting portion 21B irrespective of the front and back of the
protruding portion 31C or the tops and bottoms of the tabular
portions 31A when attaching the first attachment member 31 to the
first annular portion 21, and workability improves.
In FIG. 2 and FIG. 3, the second attachment member 32 is a
cylindrical member that is made of metal, for example, is placed on
an inner peripheral side of the second annular portion 22, and is
connected to the vehicle body 14 (FIG. 1). A bolt 36 (FIG. 1), for
example, fastened to the vehicle body 14 is inserted through the
second attachment member 32.
In FIG. 1 to FIG. 4, the first rubber elastic body 41 is disposed
between the first annular portion 21 and the first attachment
member 31 and elastically interconnects the first annular portion
21 and the first attachment member 31. Specifically, for example,
the first rubber elastic body 41 is vulcanized and molded on the
outer peripheral surface of the center portion 31D of the first
attachment member 31 and is vulcanized and adhered to the inner
peripheral surface of the first annular portion 21.
In FIG. 2 and FIG. 3, the second rubber elastic body 42 is disposed
between the second annular portion 22 and the second attachment
member 32 and elastically interconnects the second annular portion
22 and the second attachment member 32. Specifically, for example,
the second rubber elastic body 42 is vulcanized and molded on the
outer peripheral surface of the second attachment member 32 and is
vulcanized and adhered to the inner peripheral surface of the
second annular portion 22.
Hollow portions 38 and 40 are formed on both sides of the second
attachment member 32 in the axial direction of the connecting stay
portion 24. The hollow portions 38 and 40 penetrate the second
rubber elastic body 42 along the axial direction of the second
attachment member 32. A rubber connecting portion 44 is formed
between the hollow portions 38 and 40. The second attachment member
32 is elastically supported in the rubber connecting portion 44
with respect to the second annular portion 22.
(Action)
The present embodiment is configured as described above, and the
action thereof will be described below. In FIG. 1, the torque rod
10 pertaining to the present embodiment is attached between the end
portion 12A of the power unit 12 and the vehicle body 14 and is
used. According to the torque rod 10, the torque rod 10 can
elastically limit the power unit 12 from being displaced in the
rolling direction and the vehicle body front-and-rear direction,
for example, due to the torque reaction force and inertial force of
the power unit 12.
Further, in a case where the second annular portion 22 has become
relatively displaced a predetermined amount or more in the axial
direction of the connecting stay portion 24 with respect to the
second attachment member 32, the inner wall surfaces of the hollow
portions 38 and 40 come into contact with one another, or those
inner wall surfaces and the second attachment member 32 come into
contact with one another, whereby further relative displacement of
the second annular portion 22 can be limited.
Additionally, at the time of a vehicle collision, the torque rod 10
becomes broken downward in the following way. In the torque rod 10,
the thin-walled portion 21A is disposed in the region of the first
annular portion 21 exposed to the cavity portion 30 between the
upper fork portion 24U and the lower fork portion 24L of the
connecting stay portion 24, and the projecting portion 21B formed
convexly in the axial direction of the first annular portion 21 is
disposed on the thin-walled portion 21A, so when, at the time of a
vehicle collision, a predetermined load or greater has been input
from the power unit 12 to the first attachment member 31 and that
load has been further transmitted from the first attachment member
31 to the first annular portion 21, it becomes easier for stress
concentration to arise in the thin-walled portion 21A of the first
annular portion 21 having the projecting portion 21B.
Here, the projecting portion 21B is disposed in a position
intersecting the planar direction of the tabular portions 31A, for
example, which is the direction in which a load is input to the
first attachment member 31, and the protruding portion 31C that
protrudes in such a way as to approach the projecting portion 21B
is disposed in the position on the first attachment member 31
opposing the projecting portion 21B, so when the predetermined load
or greater is input to the first attachment member 31, the first
rubber elastic body 41 elastically deforms, whereby the protruding
portion 31C of the first attachment member 31 quickly contacts the
projecting portion 21B of the first annular portion 21. Because of
this, the load that has been input to the first attachment member
31 is quickly and concentratedly input to the projecting portion
21B, and a large stress concentration arises in the thin-walled
portion 21A of the first annular portion 21A. Because of this, as
shown in FIG. 5A, the first annular portion 21 can be allowed to
break more reliably starting at the thin-walled portion 21A.
Further, because of this, the first attachment member 31 becomes
movable backward into the cavity portion 30.
In addition to this, in the present embodiment, the connecting stay
portion 24 has the upper fork portion 24U that is connected to the
upper side of the first annular portion 21 and the lower fork
portion 24L that is connected to the lower side of the first
annular portion 21, and the bending strength of the lower fork
portion 24L is set relatively lower than that of the upper fork
portion 24U further reinforced by the ribs 28, so the lower fork
portion 24L reliably breaks when the predetermined load or greater
is input to the first attachment member 31.
Moreover, as shown in FIG. 5B, the sloping surface 24A whose lower
side slopes toward the second annular portion 22 is formed in the
region of the cavity portion 30 opposing the first annular portion
21, so the first attachment member 31 that has moved backward into
the cavity portion 30 comes into contact with the sloping surface
24A and is thereafter guided on the sloping surface 24A and moves
downward toward the vehicle rear side (in the direction of arrow
A). The power unit 12 (FIG. 1) is connected to the first attachment
member 31, and the power unit 12 can be allowed to fall out
downward more reliably as a result of the torque rod 10 breaking
downward as described above and the first attachment member 31
moving downward.
In this way, in the present embodiment, by disposing the difference
in bending strength between the upper fork portion 24U and the
lower fork portion 24L of the connecting stay portion 24 and giving
the torque rod 10 a structure that uses the thin-walled portion 21A
and the projecting portion 21B disposed on the first annular
portion 21 to allow stress concentration to arise in the first
annular portion 21, the load (breaking load) at which the torque
rod 10 breaks at the time of a vehicle collision can be easily
set.
(Other Embodiments)
The first annular portion 21 and the second annular portion 22 are
both configured in substantially annular shapes, but these may also
be ring-shaped portions other than circular used in the field of
torque rods.
Further, the upper fork portion 24U of the connecting stay portion
24 is reinforced by the ribs 28, but it is not limited to this, and
the ribs 28 do not have to be disposed provided that the bending
strength of the lower fork portion 24L can be set to relatively
sufficiently low by, for example, making the upper fork portion 24U
sufficiently thicker than the lower fork portion 24L. Moreover, the
connecting stay portion 24 is configured as a bifurcated structure
having the upper fork portion 24U and the lower fork portion 24L,
but it is not limited to this and may also be a structure having
three or more forks provided that the same action and effects as
those of the present embodiment are obtained.
Further, the projecting portion 21B of the thin-walled portion 21A
of the first annular portion 21 is disposed in the position
intersecting the direction in which a load is input to the first
attachment member 31, but the projecting portion 21B may also be
disposed in a position on the thin-walled portion 21A not
intersecting the direction in which a load is input.
The protruding portion 31C is disposed in the position on the first
attachment member 31 opposing the projecting portion 21B, but the
first attachment member 31 is not limited to this and may also be
configured to not have the protruding portion 31C.
REFERENCE SIGNS LIST
10 Torque Rod 12 Power Unit 14 Vehicle Body 21 First Annular
Portion 21A Thin-walled Portion 21B Projecting Portion 22 Second
Annular Portion 24A Sloping Surface 24L Lower fork Portion 24U
Upper fork Portion 24 Connecting Stay Portion 28 Ribs 30 Cavity
Portion 31 First Attachment Member 31C Protruding Portion 32 Second
Attachment Member 41 First Rubber Elastic Body 42 Second Rubber
Elastic Body
* * * * *